<?php
declare(strict_types=1);
namespace SimpleDingTalk\util\encrypt;
use Exception;
use think\facade\Log;

class Prpcrypt
{
	public $key;

	function __construct($k)
	{
		$this->key = base64_decode($k . "=");
	}

	public function encrypt($text, $corpid)
	{

		try {
			//获得16位随机字符串，填充到明文之前
			$random = $this->getRandomStr();
            $text = $random . pack("N", strlen($text)) . $text . $corpid;
		
            $iv = substr($this->key, 0, 16);

			// 网络字节序
			// $size = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
			// $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
			
			//使用自定义的填充方式对明文进行补位填充
			$pkc_encoder = (new PKCS7Encoder());
			$text = $pkc_encoder->encode($text);
			// mcrypt_generic_init($module, $this->key, $iv);
			// //加密
			// $encrypted = mcrypt_generic($module, $text);
			// mcrypt_generic_deinit($module);
            // mcrypt_module_close($module);
        

            

            $encrypted = openssl_encrypt($text, 'AES-256-CBC', $this->key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv );

			//print(base64_encode($encrypted));
			//使用BASE64对加密后的字符串进行编码
			return array(ErrorCode::$OK, base64_encode($encrypted));
		} catch (Exception $e) {
			print $e;
			return array(ErrorCode::$EncryptAESError, null);
		}
	}

	public function decrypt($encrypted, $corpid)
	{

		try {
			$ciphertext_dec = base64_decode($encrypted);
			// $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
		
			$iv = substr($this->key, 0, 16);
			// mcrypt_generic_init($module, $this->key, $iv);

			// $decrypted = mdecrypt_generic($module, $ciphertext_dec);
			// mcrypt_generic_deinit($module);
            // mcrypt_module_close($module);
            
            $decrypted = openssl_decrypt ( $ciphertext_dec, 'AES-256-CBC', $this->key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv );

        
           // return $decrypted;
		} catch (Exception $e) {
			return array(ErrorCode::$DecryptAESError, null);
		}


		try {
			//去除补位字符
			$pkc_encoder = (new PKCS7Encoder());
			$result = $pkc_encoder->decode($decrypted);
			//去除16位随机字符串,网络字节序和AppId
			if (strlen($result) < 16)
                return "";
				
			$content = substr($result, 16, strlen($result));
			$len_list = unpack("N", substr($content, 0, 4));
			$xml_len = $len_list[1];
			
			$xml_content = substr($content, 4, $xml_len);
			
			$from_corpid = substr($content, $xml_len + 4);
		} catch (Exception $e) {
			print $e;
			return array(ErrorCode::$DecryptAESError, null);
		}
		if ($from_corpid != $corpid)
            return array(ErrorCode::$ValidateSuiteKeyError, null);
            
        
		return array(0, $xml_content);

	}

	function getRandomStr()
	{

		$str = "";
		$str_pol = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz";
		$max = strlen($str_pol) - 1;
		for ($i = 0; $i < 16; $i++) {
			$str .= $str_pol[mt_rand(0, $max)];
		}
		return $str;
	}

}
